Mastering man Pages Part 1: Basics for LFCS Certification

# Task 1: Open ls man page
man ls

# Task 2: Navigate forward
Press Space  # Move forward one screen
Press Space  # Again
Press Space  # Again

# Task 3: Navigate backward
Press b  # Move back one screen
Press b  # Again

# Task 4: Jump to end
Press G  # (uppercase G)
# You're now at the end

# Jump to beginning
Press g  # (lowercase g)
# Back at the start

# Task 5: Quit
Press q

# Timing practice
time man ls
# Navigate through
# Press q
# Check how long it took

# Task 1: Open cp man page
man cp

# Task 2: Search for "recursive"
Press /
Type: recursive
Press Enter
# Jumps to first occurrence

# Task 3: Jump through matches
Press n  # Next match
Press n  # Next match
Press N  # Previous match (capital N)

# Task 4: Search backward
Press ?
Type: directory
Press Enter

# Task 5: Find preserve attributes option
Press /
Type: preserve
Press Enter
# Find: -p or --preserve option
# Or: -a (archive mode, which preserves everything)

Press q to quit

# Task 1: Read SYNOPSIS
man mkdir

# SYNOPSIS section shows:
# mkdir [OPTION]... DIRECTORY...

# Task 2: Required arguments
# DIRECTORY... is required (no brackets around it)
# At least one directory name must be provided

# Task 3: Optional arguments
# [OPTION]... is optional (in square brackets)
# Can specify zero or more options

# Task 4: Test understanding
mkdir testdir1                    # Valid: one directory
mkdir testdir2 testdir3           # Valid: multiple directories
mkdir -p /tmp/a/b/c               # Valid: option + directory
mkdir -p -v /tmp/test             # Valid: multiple options

# Without directory (should fail)
mkdir
# Error: missing operand

# Task 5: Document symbols
cat << 'EOF'
SYNOPSIS Notation:
- [OPTION] = Optional (square brackets)
- DIRECTORY = Required (no brackets)
- ... = Can repeat (ellipsis)
- | = Choose one (pipe/OR)
- bold = Type exactly
- italic = Replace with your value
EOF

# Task 1: Default passwd (section 1)
man passwd
# Header shows: PASSWD(1)
# About: passwd command
Press q

# Task 2: Section 5 passwd
man 5 passwd
# Header shows: PASSWD(5)
# About: /etc/passwd file format
Press q

# Task 3: Compare
echo "Section 1: Command usage (how to run passwd)"
echo "Section 5: File format (structure of /etc/passwd)"

# Task 4: crontab in different sections
man 1 crontab
# About: crontab command
Press q

man 5 crontab
# About: crontab file format
Press q

# Task 5: When to use which
cat << 'EOF'
Use Section 1 when:
- Learning how to run a command
- Checking command options
- Need usage examples

Use Section 5 when:
- Editing configuration files
- Understanding file format
- Need to know field meanings

Use Section 8 when:
- Using administrative commands
- Need root-level operations
EOF

# Task 1: ls sort by time
man ls
/sort.*time
# Or: /^  -t
# Answer: -t option
# Time it: time to find answer

# Task 2: tar extract
man tar
/extract
# Answer: -x option
# Even faster: know it's usually x for extract

# Task 3: cp never overwrite
man cp
/overwrite
# Find: -n or --no-clobber option

# Task 4: /etc/group file format
man 5 group
# Read NAME and DESCRIPTION sections
# See field format explanation

# Task 5: useradd home directory
man useradd
/-d
# Or: /home.*dir
# Find: -d, --home-dir

# Practice timing
echo "=== Speed Practice Log ==="
echo "Task 1: ls sort - X seconds"
echo "Task 2: tar extract - X seconds"
echo "Task 3: cp no overwrite - X seconds"
echo "Task 4: group format - X seconds"
echo "Task 5: useradd home - X seconds"
echo "Total time: X seconds"

# Task 1: Find all sections for hostname
man -wa hostname
# Output shows paths to all hostname man pages

# Alternatively, try each section
man 1 hostname  # Usually exists
man 5 hostname  # May exist
man 7 hostname  # May exist

# Task 2 & 3: Read and compare
man 1 hostname
# About: hostname command usage
# Shows: hostname, hostname -i, hostname -f, etc.
Press q

man 5 hostname
# About: /etc/hostname file format
# Shows: File structure and syntax
Press q

man 7 hostname
# About: hostname resolution concepts
# Shows: How hostname resolution works
Press q

# Task 4: Document findings
cat << 'EOF'
hostname Sections Comparison:
- Section 1: Command usage (temporary changes)
- Section 5: File format (/etc/hostname for permanent)
- Section 7: Concepts and theory

For permanent change: Use section 5 to understand
/etc/hostname file format, or use hostnamectl (section 1)
EOF

# Task 1 & 2: Study find SYNOPSIS
man find
# SYNOPSIS shows:
# find [-H] [-L] [-P] [-D debugopts] [-Olevel] [starting-point...] [expression]

# Task 3: Analyze
# Optional: [-H] [-L] [-P] [-D debugopts] [-Olevel]
# Optional with default: [starting-point...] (defaults to current dir)
# Optional: [expression] (defaults to showing all files)

Press q

# Task 4 & 5: Create and test commands
# Command 1: Minimal (all optional)
find
# Valid! Uses current dir, shows all files

# Command 2: With starting point
find /etc
# Valid! Lists all files in /etc

# Command 3: With expression
find /home -name "*.txt"
# Valid! Find .txt files in /home

# Command 4: Multiple starting points
find /etc /var -name "*.conf"
# Valid! Search multiple directories

# Command 5: With options
find -L /tmp -name "*.log"
# Valid! Follow symlinks, find .log files

# Document understanding
cat << 'EOF'
SYNOPSIS Breakdown:
- Everything in square brackets [] is optional
- ... means can repeat
- If starting-point omitted, uses current directory
- If expression omitted, lists all files
EOF

# Start timer
start_time=$(date +%s)

# Task 1: rm prompt option
man rm
/prompt
# Or: /-i
# Answer: -i, --interactive=always
Press q

# Task 2: tar verbose
man tar
/verbose
# Or: /-v
# Answer: -v
Press q

# Task 3: chmod add execute
man chmod
/execute
# Or: /symbolic
# Answer: +x (e.g., chmod +x file)
Press q

# Task 4: grep line numbers
man grep
/line.*number
# Or: /-n
# Answer: -n, --line-number
Press q

# Task 5: ps all processes
man ps
/all.*process
# Or search: /every
# Answer: -e or -A or aux
Press q

# End timer
end_time=$(date +%s)
duration=$((end_time - start_time))
echo "Total time: $duration seconds"
echo "Target: 180 seconds (3 minutes)"

if [ $duration -lt 180 ]; then
    echo "✅ Success! Under 3 minutes!"
else
    echo "⏱️  Practice more to improve speed"
fi

# Task 1: fstab format
man 5 fstab
# Note: Must specify section 5!
# Read DESCRIPTION section
# Fields: device, mountpoint, filesystem, options, dump, pass
Press q

# Task 2: Identify fields
cat << 'EOF'
/etc/fstab fields (man 5 fstab):
1. Device: What to mount (/dev/sda1, UUID=...)
2. Mount point: Where to mount (/home, /boot)
3. Filesystem: Type (ext4, xfs, nfs)
4. Options: Mount options (defaults, rw, noexec)
5. Dump: Backup frequency (0 or 1)
6. Pass: fsck order (0, 1, or 2)
EOF

# Task 3: hosts format
man 5 hosts
# Format: IP_address canonical_hostname [aliases...]
# Example: 127.0.0.1 localhost localhost.localdomain
Press q

# Task 4: Compare crontab sections
man 1 crontab
# Shows: How to use crontab command
# Commands: crontab -e, crontab -l, crontab -r
Press q

man 5 crontab
# Shows: Format of crontab files
# Fields: minute hour day month weekday command
Press q

# Task 5: Document usage
cat << 'EOF'
When to use Section 1 vs Section 5:

Section 1 (Commands):
- Learning how to RUN a command
- Need command-line options
- Want usage examples
- Example: man 1 crontab (how to edit crontab)

Section 5 (File Formats):
- EDITING a configuration file
- Understanding file structure
- Need field descriptions
- Example: man 5 crontab (crontab syntax)

Rule: If you're editing a file, use section 5!
EOF

# Task 1: ls sort by size
man ls
/size
# Find: -S (capital S)
# Test it
ls -lS /etc | head

# Task 2: umask default permissions
man umask
# Or: man 2 umask (system call)
# Or: built-in command, check bash man page
man bash
/umask
# Default: usually 0022 (resulting in 644 for files, 755 for dirs)

# Task 3: cp preserve all attributes
man cp
/preserve
# Find: -a (archive) or -p
# -a = -dR --preserve=all

# Task 4: SIGKILL number
man 7 signal
# Find: SIGKILL = 9
# Or search:
/SIGKILL
# Shows: 9

# Task 5: mkdir parent directories
man mkdir
/parent
# Find: -p, --parents

# Verify all answers
echo "=== Answers ==="
echo "1. ls sort by size: -S"
echo "2. umask default: 0022"
echo "3. cp preserve all: -a or --preserve=all"
echo "4. SIGKILL number: 9"
echo "5. mkdir parents: -p"

# Task 1: Create tar.gz
man tar
/compress
# Or: /gzip
# Find: tar -czf archive.tar.gz files
# -c = create, -z = gzip, -f = filename

# Task 2: Extract tar.gz
# Same man page
/extract
# Find: tar -xzf archive.tar.gz
# -x = extract

# Task 3: Disk usage
man du
# NAME: disk usage
# Basic: du -h directory
# Summary: du -sh directory

# Task 4: Change ownership
man chown
# SYNOPSIS: chown [OPTION]... [OWNER][:[GROUP]] FILE...
# Example: chown user:group file

# Task 5: Find files modified in 7 days
man find
/-mtime
# Find: -mtime n (n=days)
# Solution: find /path -mtime -7
# -7 = within last 7 days

# Create cheat sheet
cat << 'EOF'
Emergency Quick Reference:
1. Create tar.gz: tar -czf archive.tar.gz files/
2. Extract tar.gz: tar -xzf archive.tar.gz
3. Disk usage: du -sh directory
4. Change owner: chown user:group file
5. Find modified: find /path -mtime -7
EOF

# Task 1: passwd vs chpasswd
man passwd
# Interactive password change
# Usage: passwd [username]
# SEE ALSO section shows related commands
Press q

man chpasswd
# Batch password changes
# Reads username:password pairs from stdin
Press q

# Task 2: useradd vs adduser
man useradd
# Low-level utility
# Requires specifying all options
Press q

man adduser
# High-level, interactive (on Debian/Ubuntu)
# Or might be a script wrapping useradd
Press q

# Task 3: Check SEE ALSO sections (already done above)

# Task 4 & 5: Create comparison
cat << 'EOF'
Command Comparisons:

passwd vs chpasswd:
- passwd: Interactive, one user at a time
- chpasswd: Batch mode, multiple users from file
- Use passwd for: Single user password changes
- Use chpasswd for: Bulk password updates

useradd vs adduser:
- useradd: Low-level, requires options
- adduser: Interactive, user-friendly (Debian)
- Use useradd for: Scripts, precise control
- adduser: Manual user creation (if available)

Finding Related Commands:
- Always check SEE ALSO section
- Discover related tools
- Learn alternative approaches
EOF

# Task 1 & 2: Find OPTIONS
man cp
# Navigate to OPTIONS section
/^OPTIONS
Press Enter

# Task 3: Read -i option
/-i,
# Shows: -i, --interactive
# Prompt before overwrite

# Task 4: Read -n option
/-n,
# Shows: -n, --no-clobber
# Do not overwrite existing file
Press q

# Task 5: Test both options
# Setup
echo "original content" > test1.txt
echo "original content" > test2.txt

# Test -i (interactive)
echo "new content" > source.txt
cp -i source.txt test1.txt
# Prompts: overwrite 'test1.txt'?
# Answer: y

# Test -n (no clobber)
cp -n source.txt test2.txt
# No prompt, doesn't overwrite

# Verify
cat test1.txt  # Shows: new content
cat test2.txt  # Shows: original content

# Cleanup
rm test1.txt test2.txt source.txt

# Task 1: Find files by age
man find
/-mtime
# Find: -mtime n
# n days old: -mtime +30 (older than 30 days)

# Task 2: Execute commands on found files
# Same man page, search:
/-exec
# Find: -exec command {} \;
# {} represents the found file

# Task 3: Safe removal
man rm
# Find: -i for interactive
# Or: Use -delete option in find

# Task 4: Construct command
cat << 'EOF'
Option 1 (using -exec):
find /var/log -name "*.log" -mtime +30 -exec rm -i {} \;

Option 2 (using -delete):
find /var/log -name "*.log" -mtime +30 -delete

Option 3 (safest - preview first):
find /var/log -name "*.log" -mtime +30
# Review list, then:
find /var/log -name "*.log" -mtime +30 -delete
EOF

# Task 5: Explain each part
cat << 'EOF'
Command Breakdown:
find /var/log          - Search in /var/log directory
-name "*.log"          - Match files ending in .log
-mtime +30             - Modified more than 30 days ago
-exec rm -i {} \;      - Execute rm -i on each file
  rm                   - Remove command
  -i                   - Interactive (prompt before delete)
  {}                   - Placeholder for found filename
  \;                   - End of -exec command

Safer alternative:
-delete                - Built-in delete action (no rm)
EOF

# Practice (safe version - with -name "*.tmp" instead)
mkdir -p /tmp/practice_find
cd /tmp/practice_find
touch old1.log old2.log new.log
touch -t 202301010000 old1.log old2.log

# Find old files
find /tmp/practice_find -name "*.log" -mtime +30

# Clean up
cd ~
rm -rf /tmp/practice_find

# Task 1: Home directory
man useradd
/-d
# Find: -d, --home-dir HOME_DIR
# Or: /home.*dir

# Task 2: Shell
# Same man page
/-s
# Find: -s, --shell SHELL

# Task 3: Groups
/-G
# Find: -G, --groups GROUPS
# Supplementary groups

# Task 4: Password expiry
man passwd
# Or:
man chage
/-E
# Find: -E, --expiredate EXPIRE_DATE

# Task 5: Complete solution
cat << 'EOF'
Create user with specific requirements:

1. Create user:
sudo useradd -d /home/jdoe -s /bin/bash -G wheel,developers jdoe

Breakdown:
-d /home/jdoe     : Home directory
-s /bin/bash      : Shell
-G wheel,developers : Supplementary groups
jdoe              : Username

2. Set password:
sudo passwd jdoe

3. Set password expiry:
sudo chage -E 2025-12-31 jdoe

Verify:
id jdoe            # Check user and groups
grep jdoe /etc/passwd  # Check home and shell
sudo chage -l jdoe     # Check password policy
EOF

# If you have sudo access, test it:
# sudo useradd -d /home/testuser -s /bin/bash -G users testuser
# sudo passwd testuser
# id testuser
# sudo userdel -r testuser

# Task 1: cp with 3 arguments
man cp
# Read SYNOPSIS carefully:
# cp [OPTION]... SOURCE DEST
# cp [OPTION]... SOURCE... DIRECTORY

# Analysis:
# Three files requires last argument to be a directory!
# Solution:
mkdir destdir
cp file1 file2 file3 destdir/  # Now works!

# Task 2: rm -r prompts
man rm
/protected
# Or: /prompt
# Find: Some files are write-protected
# rm prompts for write-protected files even without -i
# Solution: Use -f to force, or fix permissions

# Task 3: @ symbols in ls -l
man ls
/@
# Or: search for extended attributes
# Find: @ indicates extended attributes (macOS)
# Or ACLs (Access Control Lists) on Linux
# Solution: Use `ls -l@` on macOS or `getfacl` on Linux

# Task 4: find *.txt issue
man find
# Read carefully: Shell expands *.txt before find sees it!
# If current dir has file1.txt, becomes: find . -name file1.txt
# Only finds that one file

# Solution: Quote the pattern
find . -name "*.txt"     # Correct
find . -name '*.txt'     # Also correct

# Task 5: Document solutions
cat << 'EOF'
Common Command Issues and Solutions:

1. cp multiple files:
   Problem: cp file1 file2 file3 (fails)
   Solution: Last argument must be directory
   Fix: cp file1 file2 file3 destdir/

2. rm -r prompts:
   Problem: Prompts even without -i
   Reason: Write-protected files trigger prompts
   Solution: rm -rf (force) or chmod first

3. @ symbols in ls:
   Problem: What does @ mean?
   Answer: Extended attributes (macOS) or ACLs
   Check: getfacl file (Linux) or ls -l@ (macOS)

4. find *.txt doesn't work:
   Problem: Shell expands * before find runs
   Solution: Quote the pattern: find . -name "*.txt"
EOF

# Task 1-3: Research and document
cat << 'EOF' > ~/man-cheatsheet.txt
Personal Linux Quick Reference (from man pages)

1. ls - List directory contents
   -l  : Long format with details
   -a  : Show hidden files (dotfiles)
   -h  : Human-readable sizes

2. cp - Copy files
   -r  : Recursive (for directories)
   -i  : Interactive (prompt before overwrite)
   -p  : Preserve attributes (permissions, timestamps)

3. mv - Move/rename files
   -i  : Interactive (prompt before overwrite)
   -v  : Verbose (show what's being done)
   -n  : No-clobber (don't overwrite existing)

4. rm - Remove files
   -r  : Recursive (for directories)
   -i  : Interactive (prompt before removal)
   -f  : Force (no prompts, ignore errors)

5. find - Search for files
   -name pattern  : Search by filename
   -mtime n       : Modified n days ago
   -exec cmd {} \;: Execute command on results

6. grep - Search file contents
   -r  : Recursive (search directories)
   -i  : Ignore case
   -n  : Show line numbers

7. tar - Archive files
   -c  : Create archive
   -x  : Extract archive
   -z  : Compress with gzip
   -f  : Specify filename

8. chmod - Change permissions
   +x  : Add execute permission
   -w  : Remove write permission
   644 : rw-r--r-- (numeric mode)

9. ps - Process status
   aux : All processes, all users, detailed
   -ef : All processes, full format
   -p  : Specific process ID

10. sudo - Execute as superuser
    -i  : Interactive shell as root
    -u user : Run as specific user
    -l  : List allowed commands

Created: $(date)
Source: All information verified via man pages
EOF

# Task 4: View your cheat sheet
cat ~/man-cheatsheet.txt

echo ""
echo "✅ Cheat sheet saved to ~/man-cheatsheet.txt"
echo "View anytime with: cat ~/man-cheatsheet.txt"

# Task 1: Find group sections
man -wa group
# Or try manually:
man 1 group  # May not exist
man 5 group  # Exists!

# Task 2: Document /etc/group format
man 5 group
# Format: name:password:GID:user_list

cat << 'EOF'
/etc/group file format (from man 5 group):
Field 1: Group name
Field 2: Group password (usually x or *)
Field 3: Group ID (GID)
Field 4: User list (comma-separated)

Example:
wheel:x:10:user1,user2,user3
EOF

# Task 3: Check for shadow section 5
man 5 shadow
# Exists! Documents /etc/shadow format
Press q

# Task 4: Compare login sections
man 1 login
# The login command
Press q

man 5 login.defs
# Or might be:
man 5 login
# Configuration file format

# Task 5: Create usage guide
cat << 'EOF'
Section Usage Guide:

Section 1 (Commands):
- How to RUN the command
- Command-line options
- Example: man 1 passwd (how to change password)

Section 5 (File Formats):
- How files are STRUCTURED
- Field descriptions
- Syntax rules
- Example: man 5 passwd (format of /etc/passwd)

Section 8 (Admin Commands):
- System administration tools
- Usually require root/sudo
- Example: man 8 useradd

Quick Rules:
- Editing /etc files? → Use section 5
- Running commands? → Use section 1
- Not sure? → Try section 1 first, then 5

Most Common for Sysadmins:
- man 5 fstab   (filesystem table)
- man 5 passwd  (password file)
- man 5 group   (group file)
- man 5 shadow  (shadow password file)
- man 5 hosts   (hostname resolution)
EOF

# Task 1: rsync SYNOPSIS
man rsync
# SYNOPSIS:
# rsync [OPTION]... SRC... [DEST]

# Analysis:
# [OPTION]... = Optional options, can repeat
# SRC... = Source(s), at least one required
# [DEST] = Optional destination

# Examples:
rsync file.txt /backup/              # Copy local file
rsync -av /data/ remote:/backup/     # Sync to remote with archive+verbose
rsync -avz user@host:/source/ /dest/ # Sync from remote with compression

# Task 2: ssh SYNOPSIS
man ssh
# SYNOPSIS:
# ssh [-l login_name] [-p port] destination [command]

# Examples:
ssh user@host                        # Basic connection
ssh -p 2222 user@host                # Custom port
ssh user@host "ls -l /tmp"           # Execute remote command

# Task 3: systemctl SYNOPSIS
man systemctl
# SYNOPSIS:
# systemctl [OPTIONS...] COMMAND [UNIT...]

# Examples:
systemctl status                     # Overall system status
systemctl start nginx                # Start nginx service
systemctl enable --now httpd         # Enable and start Apache

# Task 4: Already done above (3 examples each)

# Task 5: Document findings
cat << 'EOF'
SYNOPSIS Analysis:

rsync [OPTION]... SRC... [DEST]
- Required: SRC (at least one source)
- Optional: OPTION (can have multiple)
- Optional: DEST (some modes don't need it)

ssh [-l login_name] [-p port] destination [command]
- Required: destination (hostname or user@host)
- Optional: -l (login name)
- Optional: -p (port)
- Optional: command (interactive if omitted)

systemctl [OPTIONS...] COMMAND [UNIT...]
- Required: COMMAND (start, stop, status, etc.)
- Optional: OPTIONS
- Optional: UNIT (some commands don't need it)

Key Patterns:
- ... = can repeat
- [] = optional
- No brackets = required
- | = choose one (OR)
EOF

# Start timer
echo "=== Starting Challenge at $(date '+%H:%M:%S') ==="
start=$(date +%s)

# Task 1: Files larger than 100MB
man find
# Search: /size
# Answer: find /path -size +100M

# Task 2: Count lines
man wc
# Answer: wc -l filename

# Task 3: Change group recursively
man chgrp
# Search: /recursive
# Answer: chgrp -R groupname directory

# Task 4: View lines 10-20
man head
man tail
# Answer: head -n 20 file | tail -n 11
# Or: sed -n '10,20p' file (check man sed)

# Task 5: Find which package owns file
man rpm    # RedHat-based
# Search: /file
# Answer: rpm -qf /path/to/file

man dpkg   # Debian-based
# Answer: dpkg -S /path/to/file

# Task 6: Schedule one-time task
man at
# Answer: echo "command" | at 2pm tomorrow
# Or: at 2pm tomorrow (then enter commands interactively)

# Task 7: Unique lines
man uniq
# Answer: uniq file (on sorted file)
# Or: sort file | uniq

# Task 8: Maximum compression
man gzip
# Search: /best or /maximum
# Answer: gzip -9 filename
# Or: bzip2 -9 filename (check man bzip2)
# Or: xz -9 filename (check man xz)

# End timer
end=$(date +%s)
duration=$((end - start))

# Results
cat << EOF

=== CHALLENGE RESULTS ===
Time taken: $duration seconds
Target: 600 seconds (10 minutes)

ANSWERS:
1. Find large files: find /path -size +100M
2. Count lines: wc -l filename
3. Change group: chgrp -R groupname directory
4. Lines 10-20: head -n 20 file | tail -n 11
5. Package owner: rpm -qf file (RHEL) or dpkg -S file (Debian)
6. Schedule task: at 2pm tomorrow
7. Unique lines: uniq file (or sort file | uniq)
8. Max compression: gzip -9 file

$(if [ $duration -lt 600 ]; then
    echo "✅ EXCELLENT! You completed under 10 minutes!"
    echo "You've mastered man pages!"
else
    echo "⏱️  Good effort! Practice more to improve speed."
    echo "Review the tasks you found difficult."
fi)

EOF